1. Field of the Invention
This invention relates to a device adapted for melting and gas pressure casting.
The invention relates also to a resistance heating element suitably used for the device.
2. Prior Art
For example, centrifugal casting and pressure casting according to a lost wax process using precious metal, non-precious metal, etc. have heretofore been used for casting crown artificial teeth, artificial teeth, and the like. Out of the pressure casting, in the case of gas pressure, such a method has been employed in which the upper part of the pouring cup of a mold is covered by a water-bearing cap, and the water retained in the cap is gasified suddenly by the heat of molten metal to effect pressure casting by the steam pressure thus produced or compressed air.
As apparent from the method, the conventional gas pressure casting leaves the problem that it is primitive and depends much upon the skill and technical judgement of an operator, and is not so good in reproducibility as is generally expected.